UPDATED with memo:A report late last week that Jamie Horowitz was in line to replace NBC News chief Deborah Turness appears to be less likely with news today that Horowitz is out. In a note to staff, Turness said the SVP and GM of Today is gone effective immediately after the two decided he was not the “right fit,” and that she personally will take over Today oversight while a replacement is sought.

Horowitz hasn’t been with NBC News very long — a sort of Anne of Cleves of NBC News. In August, NBC agreed to let Bill Wolff, VP Primetime Programs at MSNBC and executive producer of The Rachel Maddow Show, out of his contract to move to ABC, in order to get that parent company to allow top ESPN programmer Horowitz take the helm at Today — three months earlier than expected. NBC had announced in May that Horowitz would start December 1, overseeing all four hours of the weekday show and the 30 Rock concert series, as NBC News struggles to regain Today’s ratings foothold. According to one insider, that official start date was still on the books so, technically, Horowitz was let go before he started, which has to be some sort of record. In reality, he’d been at the offices about 10 weeks.

“Jamie has the skills, the talent and the experience to lead the Today brand into the future,” Turness said back then. “He is first and foremost a great producer … [and] he comes at things from unexpected angles and has a popular touch combined with real intellectual creativity.”

This afternoon, however, folks inside NBC News described management styleas a cross between ferris wheel and werewolf, and that to find his lovable side you’d have to blast for it. “Vocally disrespectful to staffers from the top down,” one insider explained. “We have a pretty good esprit de corps [at Today] — a staff that hangs together, and has been through a lot. His style and presence was not helping that,” added another.

Horowitz was charged with overseeing all aspects of Today show — the program, its website and its concert series. At ESPN he had overseen Olbermann, First Take and SportsNation, among other properties. Before joining ESPN he’d worked at NBC Sports; he started his TV career as an NBC Olympics researcher.

Turness came to the network from the UK in August 2013 to help turn around the news division’s once-dominant but now struggling franchises — including Today and Meet The Press. NBC Nightly News is still ahead of ABC World News Tonight, but barely. Late last week, the New York Post reported: “Horowitz is the insider that NBC folks think has the inside shot at replacing her. He’s been kissing up to the Comcast brass with some effect.” Oops on that.

Here’s Turness’ email to staff today:

Dear All:

I want to let you know that, effective today, Jamie Horowitz will be leaving NBC News.

Jamie joined us in September as General Manager of the TODAY brand. He’s a talented producer and executive, but, together, he and I have come to the conclusion that this is not the right fit.

Because of the hard work of so many of you, and an anchor team that is hitting on all cylinders, the show has great momentum and is closing the ratings gap. The exclusives keep coming and there is a great energy both on- and off-air, and in digital and social. My focus – as always – is to support this special brand and its amazing and dedicated staff, and to position it for continued success.

The role of General Manager remains an important one, and will be filled in due course. In the interim, I will work closely with both Don Nash and Jen Brown to oversee TODAY.